Plasticized styrene-maleic resin composition



Patented Se t. 10,1946 7 t V 2,407,413 V i, rms'rroiz en smashamie RESIN I I COMPOSITION I e a r Howard L. GerharteMilwaulrec, Wi assignoritq "Pittsburgh :Plate Glass Company, Allegheny County, Pa., acorporation otlcnnsylvania' v No'Drawing ApplicationMayM', 1941," SerialNo.395,062 ,5 i

The present inventionrelates to-artificial resins and it has particularrelation to such resins as are obtained by reacting substituted or unsubstituted ethylenea-wsdicarboxylic acids or anhydrides thereof. with' a] poly'merizable olefin.

One objectfof theinventionv is to provide a clear, hard, toughystable and well, plasticized resin or the above type which is relatively free from bubbles or cavities;

A second object of the marinara May e a resinifyingfluid material thatYc'an be cast,",or-

can b'e employed]as'anl'investment median and formed into' clear, hard, durable and tough bodies at low temperatures andfwith but little distortion. A third object of the; inventionis'to provide an; improved method of. incorporatingfla,fplasticizer with the resin; I V

These and other objects will be apparent from '7 consideration of theflfollowing specification; and

the appended claims. v

It has heretofore beenproposed to heat an unsaturated dicarboxylic acidfsuchjas maleic acid or its anhydride and a polymerizableolefln such as styrene to Obtain polymerization products of white powdery character, which are soluble in acetone and dilute alkalies My copending application ,Serial .No. 242,127,

filedNovember-23, 1938, nowPatent'No. 2,297,351,

is based upon the-discovery that unsaturated dicarboxylic acids of the type of jmaleic acid, or maleic anhydride, or fumaric acid, or substituted ,maleic or fumaricacid and polymerizable .oleflns of the type of'styrene will under the influence of actinic. radiation react to form clear and hard resins which are relatively insoluble and substantiallyjfree of 'voids} Theseresins are well adapted for molding, cutting, pressing, or'otherwise form-' 'ing into bodies of great beauty. The resin-forming reaction may be carried out completely or at least in its final stages bycasting the'reacting mass in a suitable mold, thus obtainin directly prior to or during polymerization, but preferably ii Claims. (oi. 204%158) before solidification, withoutobiectionable effects upon the reaction. The, resin, under appropriate donditionasetsinto a transparenhhard, bubble free,iiand weilplasticized solid, which is" not sub- Eject toiwarpingand, cracking and which main tains'its properties well upon aging.

I The reaction to form the new resins is typified by that between'maleic acid or maleic acid anyhydride' and styrene. The two'com'pounds, along with anv ester oilevulinic acid, are ,simpiy'admixed directly or are introducedinto a solvent :suchas triacetin. and are then caused to react by actinic irradiationatq'atemperature within the range of about to Irradiation of the reactants may be continued throughout the period of reaction, but it maybe discontinued after the reaction has started. It is also possible to introduce a smallamountle-g. 1 t mes) of preliminarily irradiated reactants into the main batch and thus to obviate further irradia- *ti'on.

"Reaction may also be initiated by application .of-heatandafter it has progressed sufliciently far,'heatingis discontinued. .If very hard prod- 25 ucts'iare desired the massmay ,be ,finally heat treated at a-suitable temperature (e g,

200 C.) until the desired stage is reached. .The reaction can be brought to completion within an hour or less, but by redu cing the degree or time of-irradiation it is possible to extend it ofv'er a period of several days. The reaction product obtained from maleic an "hydride and styrene may be represented by the formula.

Where :0 represents the number of the foregoing Y groupsin the molecule and is of variable value.

Since the reaction isgeneral in character and applies to many unsaturated dicarboxylic acids or anhydrides; i. e., substituted maieic or fumaric acid and to' many of the polymerizable olefins, the product may be represented by the type formula:

where the groups R1, R2, R3, R4, R5, R6, may be practically any of the possible substituent groups. Ex'amplesof a few. of the possibilities include hy- 'drogen and chlorine, carbonyl, carboxyl, alkyl,

' aromatic and the like groups. Examples of posemployed to retardreaction.

slble ethylene a p dicarboxylic acids or ethylenic dicarboxylic acids which are transi'ormable to a form, which may be'employed, include 'maleic acid (above described), fumaric acid, the mono or di chloro substituted maleic and fumaric acids, alkylated maleic and fumaric acids, such as itaconic, citraconic acid, mesaconic acid,'mono and di phenyl maleic acid, benzyl maleic, dibenzyl maleic, ethyl maleic, or any similar acids containing a doublebond in the chain between the two carboxyl groups.

The number of polymerizable olefinic com-.

pounds is also very large and of general character. acetate, vinyl chloride, methyl styrene, parahydroxy styrene, acrylic acid, methyl, ethyl, or other esters of acrylic acid, acrolein, unsaturated ketones, such as methyl vinyl ketone, indene, coumarone and the like.

It is to be understood that anyone or more of the dicarboxylic acids can be combined with any one or more of the olefinic compounds, to provide resins in great variety. The ratio of the dicarboxylic acid to the oleflnic compound is susceptible of wide variation, but for purposes of illustration may be considered as approximately molar.

As previously stated, the reaction can be con-.

ducted in the absence of solvents. However, in some instances it may be preferable to dissolve or admix the reactants and the plasticizer with solvents such as triacetin, acetone, methyl ethyl ketone, ethyl aceto acetate, diacetone, acetic anhydride, mesityl oxide, or any other solvent for the reactants.

oxidizing agents such as benzoyl peroxidemay be employed to speed up reaction of the resins forming materials. Reducing agents, such as hydroquinone pyrogallol, tannic acid, etc., maybe The solvents in many cases are imbibed in the resinous reaction product without dissolving the latter and when so incorporated can not readily be removed by evaporation. Therefore, they may be retained as permanent components of the resinous body. The bodies still retain their clarity, hardness and toughness and usually are bubble free. The solvated resins may be hardened by baking them for a shorttime.

As previously stated, the resinous bodies are insoluble, but it is possible to cast incipiently polymerized masses into molds in which hardening to final form is effected. It is also possible to conduct polymerization in molds formed of soft glass, Pyrex, or other material transparent to actinic rays. Likewise it is possible to introduce reactive mixtures containing at least a portion of irradiated material into opaque molds of rubber or plaster and then to complete polymerization. It is also possible to heat the resins .to the softening point and then to press them to shape.

It includes styrene above described, vinyl under heat and pressure, or the comminuted material may be mixed with further polymerizable material which by appropriate treatment will be converted into hard bonding resins. Oil-soluble V dyes, such as Thodamin B. Victoria Green and pigments such'as titanium dioxide may be incoris illustrated by the following example:

containing aplasticizer in a container'of suitable A further application of the invention consists in providing a layer of polymerizable materials and plasticizer between two sheets of glass. By

irradiating this glass, it is possible to form a film of transparent closely adherent resin between the glass sheets, thus forming a safety glass. The materials may be partially polymerized prior to application to glass. In a similar manner this class of resins maybe employed in the lamination of wood, fabrics or other materials.

Resinous bodies can be cut to any desired form and then polished to provide a great variety of articles. The resins and scraps of the resin 'tain mutual solution of the components.

' actinic rays.

Example I v y Grams- Maleic anhydride 25 Styrene 35 Methyl levulinate 30 In the above example the mixture was P eferably brought to a temperature sufficient to ob- Polymerization'was then effected by irradiation with controlled by increase or decrease of the intensity of irradiation and or; the temperature. It can be brought to completion by irradiation with direct sunlight for a few minutes (15 or 20), followed by exposure to subdued light for some six hours. These exposures may take place at room temperature oi: slightly above, if so desired. The product may also be further hardened by heating.

But slight distortion takes place during polymerization. The resin is of exceptional clarity and is not subject to change of color upon aging. All of these qualities combine to provide a resin par excellence for embedding specimens, such as insects, flowers and biological specimens. An object, such as a beetle can be introduced into a solution of styrene and maleic acid or anhydride size and shape and the reaction to form the solid resin effected, at temperatures sufliciently low to obviate damage to th specimen, merely by mild irradiation. There is no damage to the specimen, due, to shrinkage and distortion of the medium during setting. The reaction is sufficiently rapid to be commercially feasible. I Example II A sample of a solution from Example I was placed between two glass plates of soft gloss and irradiated for one hour as described. The resin 1 formed as a thin film between the plates which were not easily separated.

' Example III,

A portion of the solution of Example I was irradiated for five minutes until it had congealed to incipient gellation (the mass could still be poured). This enabled more of the material to be placed between the plates. During the second 15 minutes of irradiation, pressure was applied to the plates: The finished plates adhered well and shattered with difficulty.

In the foregoing examples the dicar'boxylic acids and their anhydrides are to be considered as equivalents, since each anhydride is derived from the acid merely by elimination of a mole may be shredded or powdered and then molded of water and the ester. is the same regardless The rate of polymerization was 01' whether the acid or the anhydride is employed. Therefore, the term anhydride in the claims includes the acids and the term acid includes the anhydrides.

The embodiments of the invention herein described are merely exemplary and numerous modifications may be madetherein without departure from the spirit of the invention or the scope of the appended claims. What I claim is:

1. A method of forming clear; hard and strong plasticized bodies of styrene-maleic anhydride 5. A method of forming a hard, strong plasticized 'styrene-maleic anhydride resin which resin, which method comprises admixing styrene,

maleic acid and methyl levulinate and then sub-.

plasticized bodie of styrene-maleic anhydride resin, which method comprises mutually dissolvmg heating maleic anhydride, styrene and methyl levulinate, then polymerizing the maleic anhydride and styrene in the solution to form said resin.

4. A process as defined in claim 3, in which the polymerization is effected by irradiation with actinic rays 'at a temperature 01 about to 50 C.

comprises conjointly polymerizing about parts by weight styrene and about 25 parts by weight of maleic anhydride in solution in methyl levulinate to form a resinous body in which the methyl levulinate is imbibed as a plasticizer.

6. A process as defined in claim 5 in which the methyl levulinate is in a ratio of about 30 parts by weight.

7. A process a defined in claim-5 in which the polymerization is effected by irradiating the solution with light at about 20 to C.

a. A process as defined in claim 5111 which polymerization is efl'ected by heating the solution to reaction temperature.

9. A process as defined in claim 5 in which I about 30 parts by weight of methyl levulinate is employed and the polymerization is effected by irradiating the ingredients with actinic rays ata temperature of about 20 to 50 C.

10. A process a defined in claim 5 in which polymerization is effected by heating the materials approximately to the range of to 200 C.

11. A process as defined in claim 5 in which the methyl levulinate is in a ratio of about 30 parts by weight and polymerization is effected by heating the materials up to a temperature within the approximate range of 100 to 200 C,

HOWARD L. GERHART. 

